Walmart offers the Castrol Edge 0W-20 Full Synthetic Motor Oil 5-Quart Bottle for $19. Choose in-store pickup to avoid the $5.99 shipping fee. (Amazon charges the same with free shipping for Prime members, although it's out of stock until March 18.) That's tied with our mention from two weeks ago and the lowest price we could find by $20. It's designed for vehicles with over 75,000 miles.